HGF and teratoma: In previous papers we analyzed c-MET and HGF expression in biopsies derived from patients affected by testicular germ cell tumors (TGCTs), concluding that non-seminomas (embryonal carcinoma, yolk sac tumor, and teratoma) present the highest expression level of this receptor on the plasma membrane [4] and, besides this, embryonal carcinoma has the highest expression of HGF in the tumor microenvironment with respect to seminoma lesions [5].